More gracefully handle crashes in pytest.

When the pytest executable is executing, there is some
possibility that it can crash (due to a bug in C extensions,
for instance).  In the current code, this circumstance causes
the main colcon property to return a non-zero exit number.

But that doesn't seem correct; colcon didn't fail, one of the
tests did.  The test should be marked as failing, but colcon
itself should return a success code.  Additionally, we notice
that if a e.g. ctest test crashes, colcon returns 0.

The reason this happens only with pytest is because pytest doesn't
have a mechanism to suppress these kinds of errors.  Thus if the
python interpreter in the pytest process crashes, pytest returns
the segmentation fault number (-11 on Linux, 0xc0000005 on Windows).

Handle this by explicitly capturing this fault number, and setting
the test to failed.  Unfortunately there are no convenient constants
in Python that I could find for these numbers, so they are hardcoded
here.

This does change the user-visible functioning of colcon, but I believe
it does so for the better, and it is a bit of a corner case.

Signed-off-by: Chris Lalancette <[email protected]>

colcon_core/task/python/test/pytest.py

@@ -161,9 +161,6 @@ async def step(self, context, env, setup_py_data):  # noqa: D102
             # support pytest < 5.0
             from _pytest.main import EXIT_TESTSFAILED
             EXIT_CODE_TESTS_FAILED = EXIT_TESTSFAILED  # noqa: N806
-        if completed.returncode == EXIT_CODE_TESTS_FAILED:
-            context.put_event_into_queue(
-                TestFailure(context.pkg.name))
 
         try:
             from _pytest.main import ExitCode
@@ -172,7 +169,15 @@ async def step(self, context, env, setup_py_data):  # noqa: D102
             # support pytest < 5.0
             from _pytest.main import EXIT_NOTESTSCOLLECTED
             EXIT_CODE_NO_TESTS = EXIT_NOTESTSCOLLECTED  # noqa: N806
-        if completed.returncode not in (
-            EXIT_CODE_NO_TESTS, EXIT_CODE_TESTS_FAILED
+
+        if sys.platform == 'win32':
+            EXIT_CODE_TESTS_CRASHED = 3221225477
+        else:
+            EXIT_CODE_TESTS_CRASHED = -11
+
+        if completed.returncode in (
+            EXIT_CODE_TESTS_FAILED, EXIT_CODE_TESTS_CRASHED
         ):
+            context.put_event_into_queue(TestFailure(context.pkg.name))
+        elif completed.returncode != EXIT_CODE_NO_TESTS:
             return completed.returncode